We show that friction anisotropy is an intrinsic property of the atomic structure of Al–Ni–Co decagonal quasicrystals and not only of clean and well-ordered surfaces that can be prepared in vacuum [ J.Y. Park et al., Science 309,1354 (2005)]. Friction anisotropy is manifested in both nanometer-size contacts obtained with sharp atomic force microscope tips and macroscopic contacts produced in pi...

A contact/friction isoparametric finite element for the analysis of connections between laminated composite plates is presented. The element is compatible with a three-dimensional plate element based on layer-wise constant shear theory. The contact/friction element is based on a simple regularization of the unilateral contact with an orthotropic Coulomb friction problem. Two different friction ...

We study theoretically and numerically the kinetics of the coefficient of friction of an elastomer due to abrupt changes of sliding velocity. Numerical simulations reveal the same qualitative behavior which has been observed experimentally on different classes of materials: the coefficient of friction first jumps and then relaxes to a new stationary value. The elastomer is modeled as a simple K...

This paper comparatively studies the tribological behaviour of different types of diamond-like carbon (DLC) coatings in a reciprocating sliding wear test. The results are interpreted in terms of structure and surface morphological characteristics. At the beginning of each reciprocating sliding wear test, the higher coefficient of friction of the DLC coatings reflects the original surface condit...

The frictional behaviors of fullerenes C60 and C70 were studied because they were speculated to be solid lubricants. For the sublimated pure C60 films on Si(001), a high friction coefficient (0.55–0.8) was observed under different loads and pin materials. For the C70 film, the friction coefficient showed a pin dependence, which changed from 0.5 with an Al2O3 pin to about 0.9 with a 440 stainles...

The effects of a displacive structural phase transition on sliding friction are in principle accessible to nanoscale tools such as atomic force microscopy, yet they are still surprisingly unexplored. We present model simulations demonstrating and clarifying the mechanism and potential impact of these effects. A structural order parameter inside the material will yield a contribution to stick-sl...

this paper discusses the arching effect as the formation of a stable arch in granular materials. for this aim, a developed trapdoor apparatus is designed in order to investigate the arch dimensions in term of the internal friction angle, average size and base angle of materials. observations show that for all tested granular ensembles, width and height of the arch increase with an increase in t...

A series of experiments on friction and wear properties of carbon strip rubbing against copper contact wire is performed on high-speed friction and wear tester with electric current. The results show that the friction coefficient is generally maintained between 0.24 and 0.37. In the absence of electric current, the coefficient of friction is higher than that in the presence of electric current....

Our walking and running movement patterns require friction between shoes and ground. The surface of ice is characterized by low friction in several naturally occurring conditions, and compromises our typical locomotion pattern. Ice skates take advantage of this slippery nature of ice; the first ice skates were made more than 4,000 years ago, and afforded the development of a very efficient form...

Scanning force microscopies SFM are being routinely used to examine the mechanical and tribological properties of materials with the goal of obtaining information, such as Young’s Moduli and shear strengths from the experimental data Unertl, J. Vac. Sci. Technol. A 17, 1779 1999 . Analysis of data obtained from an SFM experiment typically requires the use of continuum mechanics models to extrac...